The present invention relates to a device of three-chamber type for purifying liquid in a cup-shaped vessel having an inlet tube for the liquid at a certain level and an outlet tube at a lower level than the inlet tube.
In the field of water purificationxe2x80x94both with regard to pretreatment and to aftertreatmentxe2x80x94the separation and storing of sinking and floating contaminants and particles is of great importance. This separation and sedimentation is accomplished in that the water is forced to flow through several chambers, where the dimensioning of each chamber is determined with regard to the sinking speeds of the contaminants and particles to separate.
A sludge separator, a septic tank of three-chamber type, or a fat separator thus consists of a container, which is divided into several chambers by vertical partition walls allowing the water or liquid to flow from chamber to chamber through openings in the walls at appropriate levels depending on the density of the contaminants or particles to separate.
These partition walls may be subjected to great pressures at sludge removal or emptying, as the liquid level may be much higher at one side of a partition wall than on the other one, which means that the partition walls must be dimensioned and attached with this difficulty in mind.
Undesired leakage may appear along the attachments of the partition walls. The partition walls of concrete are conventionally arranged in vessels of concrete, for example well rings or well pipes. For solving the above problems the partition walls have themselves to be reinforced and have to be attached by separate reinforcement bars and sealed.
This means that the conventional devices of the kind described are heavy, less volume effective, and rather expensive, although the comparatively cheap material concrete is used.
The above and other problems with a device of the kind defined above is according to the invention solved in that the vessel below the inlet and outlet tubes is vertically divided by a substantially horizontal distribution disc having at least one opening and being provided with a substantially vertical distribution tube for receiving the liquid from the inlet tube.
Hereby, a first chamber is formed below the lower end of the distribution tube, a second chamber is formed over the lower end of the distribution tube and below the distribution disc, and a third chamber is formed over the distribution disc.
In a design of this type, a sewage treatment or purification plant of biological type may be attained in that a reactor containing water purification bacteria, preferably on a carrier material, such as zeolite, and having in its lower end an air nozzle for oxygenating liquid admitted at this lower end is arranged in an opening in the distribution disc having at least one further opening. A reactor conduit connects the upper part of the reactor with the distribution tube, so that a recirculation of the liquid is accomplished.